Report on the activities of the bureau international de volcanologie from 1936–1939     

Francesco Signore 《Bulletin of Volcanology》1940,6(1):71-75

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Ground‐based InSAR reveals conduit pressurization pulses at Stromboli volcano     

Federico Di Traglia  Chiara Del Ventisette  Mauro Rosi  Francesco Mugnai  Emanuele Intrieri  Sandro Moretti  Nicola Casagli 《地学学报》2013,25(3):192-198

At Stromboli volcano (Southern Italy), only few minor precursors (gas output) have been identified for ‘major’ Strombolian explosions. We use ground‐based interferometric synthetic aperture radar (GBInSAR) technology to monitor the displacement rate of the summit area of Stromboli. We analysed the 2009–2011 period. The analysis of the displacement rate has been performed by dividing the summit zone monitored by the GBInSAR into three regions, corresponding to the edge of the crater area (1 and 2), and to the slope of the NE crater (3). Pulses of rapid expansion of sector 3, of variable duration and amplitude, appear in coincidence with periods of intense activity that include lava flows and major explosions. We associate this expansion with the pressurization of the magma column that is recharged by deep‐derived gas, promoting the onset of ‘major explosion‐dominated’ activity.  相似文献   

Improving radiometry of imaging spectrometers by using programmable spectral regions of interest     

Francesco Dell’Endice  Jens Nieke  Benjamin Koetz  Michael E. Schaepman  Klaus Itten 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(6):632-639

Programmable imaging spectrometers can be adjusted to fit specific application requirements that differ from the instrument initial spectral design goals. Sensor spectral characteristics and its signal-to-noise ratio (SNR) can be changed by applying customized online binning patterns.We present a software utility that generates application driven spectral binning patterns by using an SNR dependent sensor model. The utility, named BinGO (BInning patterN Generator and Optimiser), is used to produce predefined binning patterns that either (a) allow an existing imaging spectrometer to optimize its spectral characteristics for a specific application, (b) allow an existing imaging spectrometer to spectral and/or spatially emulate another instrument, or (c) design new multispectral or imaging spectrometer missions (i.e. spaceborne, airborne, terrestrial). We present a variety of BinGO case studies, including the simulation of airborne (APEX) [Itten, K.I. et al., 2008. APEX — The hyperspectral ESA Airborne Prism Experiment. Sensors 8(1), 1–25], spaceborne (SENTINEL III) [Nieke, J., Frerick, J., Stroede, J., Mavrocordatos, C., Berruti, B., 2008. Status of the optical payload and processor development of ESA’s Sentinel 3 mission. In: Proceedings of the Geoscience and Remote Sensing Symposium IGARSS 2008, pp. 427–430], as well as scientific and performance optimized approaches. We conclude that the presented approach can successfully be used to increase the efficiency of spectral information retrieval by using imaging spectroscopy data and to simulate various missions and requirements, finally supporting proper trade-off decisions to be made between performance optimization and scientific requirements. In addition, if specific sensor parameters are known, BinGO can also model other imaging spectrometers.  相似文献   

Radio frequency self-interference from a data processing centre at a radio telescope site     

Roberto Ambrosini  Pietro Bolli  Claudio Bortolotti  Francesco Gaudiomonte  Filippo Messina  Mauro Roma 《Experimental Astronomy》2010,27(3):121-130

Apart from externally generated Radio Frequency Interference (RFI), the occurrence of self-interference is a major concern at any modern radio telescope site. Antenna servo motor controllers, data acquisition processors, and fast computing capabilities operate very close to extremely sensitive and wideband radio astronomical receivers. In this paper, we present a set of measurements of the RFI level generated by a cluster of computers that will be installed at the site of the Sardinia Radio Telescope (SRT). The measured levels are compared to Recommendation ITU-R RA.769-2, which gives the threshold levels for interference detrimental to radio astronomy observations. Our analysis shows that, with proper shielding of the noisiest devices, it will be possible to preserve the present excellent RFI conditions of the SRT site.  相似文献   

The JCMT Legacy Survey of the Gould Belt: a first look at Orion B with HARP     

J. V. Buckle  E. I. Curtis  J. F. Roberts  G. J. White  J. Hatchell  C. Brunt  H. M. Butner  B. Cavanagh  A. Chrysostomou  C. J. Davis  A. Duarte-Cabral  M. Etxaluze  J. Di Francesco  P. Friberg  R. Friesen  G. A. Fuller  S. Graves  J. S. Greaves  M. R. Hogerheijde  D. Johnstone  B. Matthews  H. Matthews  D. Nutter  J. M. C. Rawlings  J. S. Richer  S. Sadavoy  R. J. Simpson  N. F. H. Tothill  Y. G. Tsamis  S. Viti  D. Ward-Thompson  J. G. A. Wouterloot  J. Yates 《Monthly notices of the Royal Astronomical Society》2010,401(1):204-222

The Gould Belt Legacy Survey will survey nearby star-forming regions (within 500 pc), using Heterodyne Array Receiver Programme (HARP), Submillimetre Common-User Bolometer Array 2 and Polarimeter 2 on the James Clerk Maxwell Telescope. This paper describes the initial data obtained using HARP to observe ¹²CO, ¹³CO and C¹⁸O   J = 3 → 2  towards two regions in Orion B, NGC 2024 and NGC 2071. We describe the physical characteristics of the two clouds, calculating temperatures and opacities utilizing all the three isotopologues. We find good agreement between temperatures calculated from CO and from dust emission in the dense, energetic regions. We determine the mass and energetics of the clouds, and of the high-velocity material seen in ¹²CO emission, and compare the relative energetics of the high- and low-velocity material in the two clouds. We present a clumpfind analysis of the ¹³CO condensations. The slope of the condensation mass functions, at the high-mass ends, is similar to the slope of the initial mass function.  相似文献   

Supernova remnants, planetary nebulae and the distance to NGC 4214     

Michael A. Dopita  Daniela Calzetti  Jesús Maíz Apellániz  William P. Blair  Knox S. Long  Max Mutchler  Bradley C. Whitmore  Howard E. Bond  John MacKenty  Bruce Balick  Marcella Carollo  Michael Disney  Jay A. Frogel  Robert O’Connell  Donald Hall  Jon A. Holtzman  Randy A. Kimble  Patrick McCarthy  Francesco Paresce  Abhijit Saha  Alistair R. Walker  Joe Silk  Marco Sirianni  John Trauger  Rogier Windhorst  Erick Young 《Astrophysics and Space Science》2010,330(1):123-131

We present narrow band, continuum subtracted Hα, [S ii], Hβ, [O iii] and [O ii] data taken with the Wide Field Camera 3 on the Hubble Space Telescope in the nearby dwarf starburst galaxy NGC 4214. From these images, we identify seventeen new planetary nebula candidates, and seven supernova remnant candidates. We use the observed emission line luminosity function of the planetary nebulae to establish a new velocity-independent distance to NGC 4214. We conclude that the PNLF technique gives a reddening independent distance to NGC 4214 of 3.19±0.36 Mpc, and that our current best-estimate of the distance to this galaxy ids 2.98±0.13 Mpc.  相似文献   

Hydrogeochemistry of Roccamonfina volcano (Southern Italy)   总被引：1，自引：1，他引：0  

Emilio Cuoco  Giuseppe Verrengia  Stefano De Francesco  Dario Tedesco 《Environmental Earth Sciences》2010,61(3):525-538

This is the first hydro-geochemical investigation carried out on the Roccamonfina Volcanic Complex groundwaters. The chemistry of Roccamonfina waters is defined by water–rock and water–rock–gas interactions. In fact, interactions between rocks of the first eruptive high-K formations and circulating groundwaters are recognized by high K concentrations. On the other hand, inverse concentration of calcium versus alkali metals is related to two different rock interactions occurring in different areas of the volcano: (a) within the caldera where groundwaters flow within latite and pyroclastic formations releasing calcium, and (b) similarly at the base of the volcano where groundwaters flowing from surrounding carbonates got strongly enriched in Ca. These geochemical processes are also associated with K (SE of caldera) and Mg/Ca (in sites located at the NE base of the volcano) decrease. Completely different dynamics occurs at Riardo groundwaters (SE). Here waters are the result of a mix between the Roccamonfina deep aquifer and the carbonate aquifer of the Riardo plain. Rich-CO₂ emissions make these waters strongly mineralized. Minor elements show a similar geochemical behavior of major ions and are crucial defining interactions processes. The evolution of Roccamonfina groundwaters is also evident along the simultaneous enrichment of Ba, Sr, and Ca. Ba increase is the result of deep local carbonate alteration enhanced by CO₂ emissions and, the lower Sr/Ca ratio, from 10 to 2 (ppb/ppm), is also due to the same process. In the light of our results the Roccamonfina aquifer can be schematically divided into two main reservoirs: (a) a superficial aquifer which basically follows the volcanic structure morphology and tectonics and (b) a deeper reservoir, originating within the oldest Roccamonfina volcano ultra potassic lavas and then flowing into the carbonate aquifers of the neighboring plain. Eventually, the chemistry of the Roccamonfina aquifer does not show any specific and visible pollution, contrary to what happens in the volcano surrounding plains. In fact, only 14% of the samples we collected (206) show a NO₃ content >30 mg/l. These sites are all located at the base of the volcano, near the plain.  相似文献   

First-principles calculation of H/D isotopic fractionation between hydrous minerals and water     

Merlin Méheut  Michele Lazzeri  Etienne Balan  Francesco Mauri 《Geochimica et cosmochimica acta》2010,74(14):3874-3882

Hydrogen fractionation laws between selected hydrous minerals (brucite, kaolinite, lizardite, and gibbsite) and perfect water gas have been computed from first-principles quantum-mechanical calculations. The β-factor of each phase was calculated using the harmonic phonon dispersion curves obtained within density functional theory. All the fractionation laws show the same shape, with a minimum between 200 °C (brucite) and 500 °C (gibbsite). At low temperatures, the mineral/liquid water fractionation laws have been obtained using the experimental gas/liquid water fractionation laws. The resulting fractionation laws systematically overestimate measurements by 15‰ at low temperatures to 8‰ at ≈400 °C. Based on this general agreement, all calculated laws were empirically corrected with reference to brucite/water data. These considerations suggest that the experimental or natural calibrations by Xu and Zheng (1999) and Horita et al. (2002) (brucite/water), Gilg and Sheppard (1996) (kaolinite/water), Wenner and Taylor (1973) (lizardite/water), and in some extents Vitali et al. (2001) (gibbsite/water) are representative of equilibrium fractionations. Besides, internal isotopic fractionation of hydrogen between inner-surface and inner hydroxyl groups has been computed for kaolinite and lizardite. The obtained fractionation is large, of opposite sign for the two systems (respectively, −23‰ and +63‰ at 25 °C) and is linear in T^-2. Internal fractionation of hydrogen in TO phyllosilicates might thus be used in geothermometry.  相似文献   

Contrasting physical and chemical conditions of two rock glacier springs     

Stefano Brighenti  Michael Engel  Monica Tolotti  Maria Cristina Bruno  Geraldene Wharton  Francesco Comiti  Werner Tirler  Leonardo Cerasino  Walter Bertoldi 《水文研究》2021,35(4):e14159

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Economic impacts of climate change in Europe: sea-level rise     

Francesco?BoselloEmail author  Robert?J.?Nicholls  Julie?Richards  Roberto?Roson  Richard?S.?J.?Tol 《Climatic change》2012,112(1):63-81

This paper uses two models to examine the direct and indirect costs of sea-level rise for Europe for a range of sea-level rise scenarios for the 2020s and 2080s: (1) the DIVA model to estimate the physical impacts of sea-level rise and the direct economic cost, including adaptation, and (2) the GTAP-EF model to assess the indirect economic implications. Without adaptation, impacts are quite significant with a large land loss and increase in the incidence of coastal flooding. By the end of the century Malta has the largest relative land loss at 12% of its total surface area, followed by Greece at 3.5% land loss. Economic losses are however larger in Poland and Germany (483 and483 and 391 million, respectively). Coastal protection is very effective in reducing these impacts and optimally undertaken leads to protection levels that are higher than 85% in the majority of European states. While the direct economic impact of sea-level rise is always negative, the final impact on countries’ economic performances estimated with the GTAP-EF model may be positive or negative. This is because factor substitution, international trade, and changes in investment patterns interact with possible positive implications. The policy insights are (1) while sea-level rise has negative and huge direct economic effects, overall effects on GDP are quite small (max −0.046% in Poland); (2) the impact of sea-level rise is not confined to the coastal zone and sea-level rise indirectly affects landlocked countries as well (Austria for instance loses −0.003% of its GDP); and (3) adaptation is crucial to keep the negative impacts of sea-level rise at an acceptable level.  相似文献